This invention relates to embodiments wherein a motor protector is positioned in the non-orbiting scroll, and the necessary wires extend through the non-orbiting scroll in a fashion such that a discharge chamber is sealed from a suction chamber around the wires.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor a first scroll member has a base and a generally spiral wrap extending from its base. A second scroll member has a base and a generally spiral wrap extending from its base. The wraps of the two scroll compressors interfit to define compression chambers. The second scroll member is caused to orbit relative to the first. As the two orbit relative to each other, compression chambers between the two are decreased in volume compressing an entrapped refrigerant. Typically, the scroll compressor pump unit including the two scroll members is housed within a sealed housing. The housing is typically divided into both the suction chamber and a discharge pressure chamber. The suction refrigerant leading to the compressor passes over a motor for driving the second scroll member, cooling the motor.
It is known to include a motor protector into the sealed compressor housing. Typically the motor protector has been positioned near the motor, and is operable upon sensing extreme temperature or extreme electrical characteristics to stop operation of the motor. This will protect the compressor, and will also protect any system to which the compressor is connected.
It has also been proposed to move the motor protector to a location more adjacent to the compressor pump unit. Thus, in co-pending U.S. patent application Ser. No. 09/527,428, filed Mar. 16, 2000 and entitled xe2x80x9cMotor Protector on Non-Orbiting Scrollxe2x80x9d, it has been proposed to position the motor protector in the first scroll member base. Further, in co-pending U.S. patent application Ser. No. 09/702,623, filed Oct. 31, 2000 and entitled xe2x80x9cScroll Compressor With Motor Protector in Non-Orbiting Scroll and Flow Enhancementxe2x80x9d, it has been proposed to include systems for increasing the flow of discharge pressure refrigerant over the motor protector. In particular, in the event of a system fault the discharge pressure refrigerant is likely to be at an elevated temperature. Further, the refrigerant is likely to be at an elevated pressure. Thus, the above-referenced co-pending U.S. patent application Ser. No. 09/702,623 proposed associating a pressure relief valve with the motor protector.
In the proposed embodiment, the motor protector is positioned in a chamber in a rear face of the non-orbiting scroll. Further, a cap is positioned in the chamber sealing the chamber from the outside refrigerant chamber. A pressure relief valve extends through the cap, and selectively communicates discharge pressure refrigerant into the chamber if the discharge pressure exceeds a suction pressure by a predetermined amount. Pressure relief valves are known, and the pressure relief valve in this application may function as known. Should the pressure differential between the discharge and suction pressure exceed a predetermined amount, the pressure relief opens and communicates the discharge pressure refrigerant into the chamber. Since the discharge pressure refrigerant tends to be at an elevated temperature, this causes the motor protector to actuate, stopping operation of the motor.
With such systems, the electric wires must lead from the motor protector down to the motor. The routing of these wires raises some issues with regard to sealing a discharge chamber from a suction chamber.
In disclosed embodiments of this invention, a motor protector is incorporated into the non-orbiting scroll. The wires are routed from the motor protector to the motor in a way which does not lead to a leak between the discharge and suction chambers.
In the disclosed embodiment of this invention, a suction pressure tap extends through the base of the first scroll member to communicate the chamber to the suction chamber. This serves not only to provide a suction pressure force to be measured against the discharge pressure by the pressure relief valve, but further serves as a conduit for communicating the motor protector to the motor. The wires which extend from the motor protector to the motor extend through this hole in the preferred embodiment. In one embodiment, a cap encloses the chamber, and the pressure relief valve is mounted in that cap. Thus, the tap remains sealed.
In a second embodiment, the pressure relief valve extends into the chamber and through a wall of the first scroll member.
In another embodiment, the wires extend to a sealing plug which seals the area outwardly of the wires such that the wires can be routed from the protector to the motor without causing any related leakage.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.